docs: def load(self):
          """Load the state from the JSON file in the config dir."""
          if not op.exists(self.path):
              logger.debug("The GUI state file `%s` doesn't exist.", self.path)
              # TODO: create the default state.
              return
          assert op.exists(self.path)
          logger.debug("Load the GUI state from `%s`.", self.path)
          self.update(_bunchify(_load_json(self.path)))